Austrian police have detained three suspects for allegedly smuggling people onto flights bound for the United States or Britain.

State Prosecutor Friedrich Koehl said Tuesday there had been at least 11 cases of smuggling between last fall and February.

The suspects worked for a private security company hired by Austrian Airlines and controlled passports and tickets at departure gates.

Those being smuggled were taken into the departure area through restricted doors and gates, Koehl said. They were then given tickets and boarding passes that had been bought by acquaintances of the suspects.

Koehl said investigations began after an illegal traveler was returned to Austria from the U.S., and a person who had been asked by the smugglers to cooperate in the scheme by buying a ticket went to the police.

The suspects were not identified in keeping with Austrian confidentiality laws.